A. Field of Invention
The present invention relates in general to sensors, and more particularly, to a pressure sensor housing and assembly.
B. Description of Related Art
Pressure measurements are generally made in process control industries (e.g., paper manufacturer, oil refinery, chemicals manufacturer, etc.), in vehicles (e.g., oil pressure in an engine), in aerospace manufacturing, in utilities and heating, and in other industries. Pressure measurements typically are made as absolute, gauge, or differential measurements. Absolute pressure sensors measure a pressure relative to a vacuum, gauge sensors measure a pressure relative to atmospheric pressure, and differential sensors measure a pressure difference between two inputs.
Pressure sensors may incorporate an xe2x80x9cup-the-tubexe2x80x9d pressure intake design to possibly accommodate differential, gauge, and absolute pressure measurements. An up-the-tube pressure sensor may be able to measure a pressure without harm to components of the sensor. For example, an up-the-tube pressure sensor may prevent fluid from contacting electronics of a sensing die. A typical up-the-tube pressure sensor has a glass header connected (via a laser-weld) to a manifold. Additionally, a printed circuit board is connected upright to the glass header using a flexible printed circuit board bond (i.e., flex-tape). Manufacturing a pressure sensor in this manner reduces the amount of space on the circuit board due to the header laser-weld and the header flex-tape bond because both the laser-weld and the flex-tape connections utilize circuit board real estate.
In addition, existing up-the-tube pressure sensors are configured such that pressure inputs and electrical outputs flow in opposing directions, causing interference between the inputs and outputs of the sensor. As a result, existing up-the-tube pressure sensors may not fulfill manufacturing and performance requirements, and so, a pressure sensor that may be manufactured without such existing difficulties and problems is desired.
In accordance with an exemplary embodiment, a unitary housing is provided that has a pressure inlet that is defined through a surface of the unitary housing. The housing also has an elongated tube positioned within the unitary housing. The elongated tube has a first end and a second end. The first end is in pressure communication with the pressure inlet. The housing also has a sensing die attached to the second end of the elongated tube such that pressure present at the pressure inlet is measurable by the sensing die.
In another embodiment, a pressure sensor assembly is provided that has a unitary housing with a first end and a second end. The first end has a surface with a pressure inlet that comprises an elongated tube. The assembly also has a sensing die with a pressure sensitive surface. The sensing die is coupled to the elongated tube and mounted such that the pressure sensitive surface is substantially perpendicular to the surface of the housing with the pressure inlet. The assembly also has a circuit board coupled to the second end of the unitary housing such that the circuit board is substantially perpendicular to the surface of the housing with the pressure inlet.
In still another embodiment, an up-the-tube pressure sensor is provided that has a unitary housing comprising a pressure inlet that is defined through a surface of the unitary housing. The housing also has a sensing die positioned within the unitary housing. The sensing die is in pressure communication with the pressure inlet. The housing further has an elongated Pyrex tube positioned within the unitary housing. The elongated Pyrex tube is in pressure communication with the pressure inlet.
These as well as other features and advantages of the present invention will become apparent to those of ordinary skill in the art by reading the following detailed description, with appropriate reference to the accompanying drawings.